Camera filters are used to alter and improve the quality of photography and video footage. Placed over the lens, camera filters improve image quality by modifying light penetration. Different classes of filters provide different functions. Environment and desired image appearance determine the appropriate filter. Neutral density filters, for example, are used for image saturation by attenuating light. There is a wide range of neutral density filters exist, providing different levels of image saturation. A polarized filter eliminates unwanted reflections and creates a clearer image. UV filters can be used to protect a filter and improve image quality. Light corrective filters can be used to compensate for irregularities caused by water quality in underwater shooting. Warming and cooling filters also correct color balance or enhance contrast or diffusion, as desired.
The quality of filters within a class vary significantly. “Class” herein is used to refer to filters capable of similar light modifying function, and traditionally given the same designation by the photography and videography industry. The light modifying element of a filter can be made from glass, polyester, gelatin or resin; all producing different quality images. Glass quality can also vary. “Light modifying element” will be used herein broadly to refer to the image altering, light transmissive component of the filter.
Choosing the right filter is vital to quality photography and videography. High quality photography requires two things above all else: capturing the right image and utilizing the right equipment to modify that image. Because of the fleeting nature of most shots or scenes, the identification and installation of the right filter on the camera must be made very quickly. Multiple steps must be taken to properly adjust the camera for the desired shot. Aperture must be adjusted for proper depth of field. Appropriate shutter speed is determined based on desired movement effect. These factors interact with each other and are also affected by filter choice. The filter must be installed on the lens by threading or pressure fitting. A photographer has many decisions to make in a limited amount of time.
Time is further constricted by obstacles in identifying the right camera filter. Filters with different functions often appear very similar in isolation. Filters configured for the same lens are required to be very similar, if not identical, in size. The light modifying element color of filters with different specifications appear similar. Neutral density filters and polarizer filters, for example, use light modifying elements of similar grayish hues or black. The light modifying element of neutral density filters with different color saturation capacities can appear nearly indistinguishable in isolation. Color corrective filter light modifying elements can also appear similar in filters intended for different settings. Difficulties caused by the similarity in light modifying element appearance is exacerbated when ambient lighting isn't ideal or the photographer is far sighted. Determining filter quality by looking at the light modifying element requires close scrutiny and manipulation of the filter.
Currently, filter specifications are indicated on the side of the filter frame in writing. This writing is necessarily miniscule because of the thinness of frames. Inspection required by the small writing is inconvenient and time consuming when a photographer is rushing to capture a transitory image opportunity. Filters must be rotated or flipped to read the specifications. The size of the writing makes reading difficult under the best conditions. Operating underwater or in nature can make this evaluation impossible, and cause a user to drop and damage, or lose the filter. The specification writing can be covered by dirt or removed by damage. These restrictions in identifying the filter prevent a photographer from quickly choosing the necessary filter, and in turn can result in the desired shot or scene vanishing before it is captured.
Advances in technology are allowing for increasingly smaller camera lens sizes. Lens housings with diameters of 1 cm2 or smaller are now capable of recording high quality images. Filters configured for these lenses can be 1 mm or smaller in thickness. These sizes prohibit written specifications that are legible to the naked eye. Identification must be achieved by an alternative method.
Organization can also be difficult when filters are only distinguished by writing on the outer frame of the filter. The user must take the time to read the individual specifications to organize the filters in meaningful order.